Compressible structural panel including components of a glass fiber matrix bonded with polyacrylic acid

ABSTRACT

A structural panel for use in building structures or in the formation, finish or decoration thereof includes an outer sheet and a connector sheet with a plurality of collapsible or compressible dividers therebetween. The panel in a rest condition is expanded and of a desired thickness for final use but can be compressed into a relatively thin thickness or profile for shipping purposes. The panel is very lightweight but structurally strong and can be selectively bent in one transverse direction if desired. The panel can be easily cut or formed into any predetermined size or shape.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/309,939 filed Dec. 3, 2002, which is a continuation-in-part of U.S.application Ser. No. 09/970,008, filed Sep. 27, 2001, which is acontinuation of U.S. application Ser. No. 09/839,373, filed Apr. 23,2001, which application claims the benefit of U.S. provisionalapplication No. 60/199,208, filed Apr. 24, 2000. This application alsorelates to co-pending application Ser. No. 10/309,944 filed Dec. 3, 2002entitled “Method and Apparatus For Fabricating Cellular StructuralPanels”. All of the above-identified applications are herebyincorporated by reference as if fully disclosed herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

A structural panel which finds particular uses as a ceiling panel orwall panel, includes an outer sheet having a plurality of spaceddividers protruding from one face thereof and a connecting sheet, or thelike, parallel to and spaced from the outer sheet connecting thedividers together along their sides distal the outer sheet. The dividersare compressible for at least some period of time when pressure isapplied thereto to reduce the thickness of the panel when desired, forexample, for shipping purposes.

2. Description of the Relevant Art

Structural panels used in the finish or decoration of buildingstructures have taken numerous forms from drywall to decorative oracoustical ceiling panels. While such panels obviously have differentcharacteristics, the panels have had numerous shortcomings, such as froma weight standpoint, a shipping standpoint, a lack of aesthetic oracoustical variety, and the like.

Some of these panels are used, for example, in drop ceiling systemswherein a gridwork of inverted T-shaped support members definerectangular openings in which acoustical panels or the like are placed.Such acoustical panels are typically rigid in nature and somewhatbrittle. As a result, they are difficult to insert or remove from thesupporting gridwork and in many cases are easily damaged during suchprocess. Further, the ceiling panels are relatively heavy and are of afixed thickness so that their shipping dimensions are the same as theirinstallation dimensions. Due in part to their weight and bulk duringshipping, the cost per square foot of such panels is relatively high.

Drywall is also relatively heavy, difficult to work with and has ashipping size identical to that of its installation size. The shippingcost for drywall is, therefore, also relatively high.

It will be appreciated from the above that structural panels used in theconstruction, finish and decoration of building structures suffernumerous shortcomings. A panel that would overcome such shortcomingswould, therefore, be desirable.

SUMMARY OF THE INVENTION

The structural panel of the present invention can be used for a numberof different purposes as will be evident to those skilled in the artupon a reading of the present disclosure. Fundamentally, however, thepanel would typically include an outer sheet of semi-rigid material witha plurality of dividers protruding from one face thereof. A connector inthe form of a sheet or similar interconnecting system is secured to thedistal edges of the dividers. The connector could take the form ofanother sheet of material, strands of connective fibers, or the like.

The dividers are compressible in nature and could take numerous forms.In some of the described embodiments, the dividers are elongated cellshaving foldable sides so that when lateral, i.e. transverse pressure isapplied to the cell in predetermined directions it will compress into ashallow space. The dividers can be formed from folding a strip ofsemi-rigid material such that the longitudinal sides or partitions foldinwardly or outwardly when the divider is compressed laterally. Thedividers are constructed so as to normally assume an expanded orextended position of predetermined configuration and are resilient so asto return to that configuration after having been compressed. Thedividers are secured to the outer sheet and the connector so as toremain in position relative thereto.

As will be appreciated, with a panel so formed, it will assume anexpanded form in its normal at rest condition, but by applying pressure,with a perpendicular component, to the outer sheet or the connector, thedividers are caused to compress allowing the entire panel to assume avery thin thickness or profile. When compressing, the outer sheet ismoved perpendicularly toward the connector sheet with the dividers beingcompressed therebetween, i.e. there is minimal, if any, sliding movementbetween the outer and connector sheets. This, of course, is veryadvantageous for shipping purposes as a greater number of panels can beconfined in a container than is possible with prior art panels that havea uniform thickness during shipping and use. The panels are alsopredominantly air filled and, therefore, are very lightweight.

It will further be appreciated from the more detailed descriptionhereafter that the panels can be bent at least in one direction tofacilitate installation in a drop ceiling or the like but are resilientto resume their normal at rest position. Further, the panels are notbrittle and do not damage easily. They can, further, be cut very simplyinto any predetermined size and/or configuration.

Decorative sheets can also be overlaid onto the outer sheet, theconnector sheet or the like of the panel to give the panel a desiredaesthetic look. For example, a sheet of wood veneer, vinyl, patterned orcontoured paper, colored paper, thin metal, polyester, other syntheticmaterial, fabric, non-woven, or the like, can be overlaid so that thepanel, when in use, has any desired appearance. Further, the panel canbe interiorly or exteriorly lined with metal foil to change acousticalor other properties of the panel.

Other aspects, features and details of the present invention can be morecompletely understood by reference to the following detailed descriptionof a preferred embodiment, taken in conjunction with the drawings andfrom the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a panel formed in accordance with thepresent invention.

FIG. 2 is a fragmentary isometric view looking upwardly at a dropceiling in a building structure, with the panels of FIG. 1 incorporatedtherein.

FIG. 3 is an enlarged fragmentary section taken along line 3-3 of FIG.2.

FIG. 4 is a front elevation of a strip of material from which a dividerof the panel of the present invention is made.

FIG. 5 is a front elevation of the strip of material shown in FIG. 4being creased to form pre-fold lines.

FIG. 6 is a front elevation of the strip of material shown in FIG. 4after having been creased as shown in FIG. 5.

FIG. 7 is a front elevation of the strip of material shown in FIG. 6having been folded along the preformed fold lines.

FIG. 8 is a front elevation of the divider as shown in FIG. 7 havingbeen compressed.

FIG. 8A is an enlarged section of the circled area of FIG. 8.

FIG. 9 is a front elevation similar to FIG. 8 with a layer of adhesiveshown in dashed lines positioned above and below the divider.

FIG. 10 is a front elevation similar to FIG. 9 with an outer sheet and aconnector sheet being positioned above and below the layers of adhesive.

FIG. 11 is a front elevation showing the composite illustrated in FIG.10 being heat compressed between heating elements.

FIG. 12 is a fragmentary end elevation of a panel formed in accordancewith the present invention and with a decorative layer of material beingadhesively secured to the outer sheet of the panel.

FIG. 13 is a fragmentary end elevation of the panel as shown in FIG. 12being compressed between heated press elements.

FIG. 14 is an end elevation of a panel as shown in FIG. 12 havingdividers with asymmetric partitions and with the panel fully expanded.

FIG. 15 is an end elevation similar to FIG. 14 with the panel beingpartially compressed.

FIG. 16 is an end elevation similar to FIG. 15 with the panel beingslightly further compressed.

FIG. 17 is an end elevation similar to FIG. 16 with the panel beingfully compressed.

FIG. 18 is an isometric view of the panel as shown in FIG. 14.

FIG. 19 is an enlarged isometric view of a portion of the panel shown inFIG. 18.

FIG. 20 is an isometric view of the panel shown in FIG. 18 in a fullycompressed condition.

FIG. 21 is an enlarged isometric view of a portion of the panel as seenin FIG. 20.

FIG. 22 is an isometric view of a plurality of panels stacked togetherwhile in a compressed condition.

FIG. 23 is an isometric view of the panels shown in FIG. 22 in anexpanded condition.

FIG. 24 is an enlarged fragmentary end elevation of the panel shown inFIG. 14 with end supports for the panel to inhibit the panel frombending.

FIG. 25 is a fragmentary section taken along line 25-25 of FIG. 24.

FIG. 26 is a fragmentary isometric with parts removed showing an endsupport on one end of the panel and a second end support being installedon the opposite end of the panel.

FIG. 27 is a fragmentary vertical section taken through a portion of thepanel illustrating an alternative embodiment of the divider wherein thedivider includes an inner layer of a metallic foil.

FIG. 28 is a fragmentary vertical section taken through the panelsimilar to FIG. 27 showing still another alternative arrangement of thedivider wherein a metal foil is applied to the outer surface of thedivider.

FIG. 29 is a transverse section taken through the panel as shown in FIG.14 with the panel being compressed on its top surface.

FIG. 30 is a section taken along line 30-30 of FIG. 29.

FIG. 31 is an end elevation of the panel shown in FIG. 14 with the panelbeing curved concave upwardly.

FIG. 32 is an end elevation of a panel in accordance with a secondembodiment of the present invention wherein the partitions of thedividers are symmetric rather than asymmetric as shown in FIG. 31.

FIG. 33 is an isometric view showing a panel in accordance with thepresent invention wherein the connection means are elongated strands orfibers that are secured to the dividers distally from the outer sheet.

FIG. 34 is an enlarged isometric showing a portion of the panelillustrated in FIG. 33.

FIG. 35 is an isometric view of the panel shown in FIG. 33 with thepanel having been bent or curved so as to be upwardly concave.

FIG. 36 is an end elevation of a panel formed in accordance with thepresent invention and corresponding to the panel shown in FIG. 32.

FIG. 37 is an end elevation of the panel shown in FIG. 36 with the panelpartially compressed.

FIG. 38 is an end elevation of the panel shown in FIG. 37 having beenfully compressed.

FIG. 39 is an isometric view of the panel shown in FIG. 38 in a fullycompressed condition.

FIG. 40 is an isometric view of a portion of the panel shown in FIG. 36in a fully expanded condition.

FIG. 41 is an isometric view of a plurality of panels of the type shownin FIG. 36 having been compressed and stacked together.

FIG. 42 is an isometric view of a portion of the panels of the typeshown in FIG. 36 having been stacked in a fully expanded condition.

FIG. 43 is a diagrammatic end elevation of a panel with asymmetricdividers illustrating dimensional characteristics thereof.

FIG. 44 is a diagrammatic end elevation of a panel with symmetricdividers illustrating dimensional characteristics thereof.

FIG. 45 is an enlarged end elevation of a portion of the panel of FIG.43 illustrating other dimensional characteristics.

FIG. 46 is an enlarged end elevation of a portion of the panel of FIG.44 illustrating other dimensional characteristics.

FIG. 47 is an end elevation similar to FIG. 45 showing the panelcompressed with a force F.

FIG. 48 is an end elevation similar to FIG. 46 showing the panelcompressed with a force F.

FIG. 49 is an isometric view of another embodiment of a divider for usein the panel of the present invention.

FIG. 50 is an end elevation of the divider shown in FIG. 49.

FIG. 51 is an end elevation of a panel including a plurality of thedividers shown in FIG. 49 in an expanded form.

FIG. 52 is a reduced end elevation of the panel shown in FIG. 51 in acompressed form.

FIG. 53 is an isometric view of still another embodiment of a dividerfor use in the panel of the present invention.

FIG. 54 is an end elevation of the divider shown in FIG. 53.

FIG. 55 is an end elevation of a panel formed in accordance with thepresent invention and utilizing the divider of FIG. 53 with the panel inan expanded form.

FIG. 56 is a reduced end elevation of the panel of FIG. 55 in acompressed form.

FIG. 57 is an isometric view of still another embodiment for a dividerfor use in the panel of the present invention.

FIG. 58 is an end elevation of the divider shown in FIG. 57.

FIG. 59 is an end elevation of a panel utilizing the divider of FIG. 57with the panel shown in an expanded form.

FIG. 60 is a reduced end elevation of the panel shown in FIG. 59 in acompressed form.

FIG. 61 is an isometric view of still another divider for use in thepanel of the present invention.

FIG. 62 is an end elevation of the divider shown in FIG. 61.

FIG. 63 is an end elevation of a panel utilizing the divider shown inFIG. 61 and with the panel in an expanded form.

FIG. 64 is a reduced end elevation of the panel shown in FIG. 63 in acompressed form.

FIG. 65 is an exploded isometric view of a panel similar to that shownin FIG. 1 that has been rigidified by providing additional dividers atthe ends of the panel that extend perpendicular to the primary dividers.

FIG. 66 is a side elevation of the panel shown in FIG. 65.

FIG. 67 is an end elevation of the panel shown in FIG. 65.

FIG. 68 is an end elevation of a further embodiment of the presentinvention in which the panel can be bent at a right angle.

FIG. 69 is an isometric view of a panel formed as in FIG. 68 with thepanel in a fully compressed condition.

FIG. 70 is a side elevation of the panel shown in FIG. 69.

FIG. 71 is an end elevation similar to FIG. 68 with the panel slightlyfurther expanded.

FIG. 72 is an isometric view of the panel of FIG. 68 having been bentalong a right angle and with the panel fully expanded.

FIG. 73 is an end elevation of the panel as shown in FIG. 72.

FIG. 74 is an fragmentary isometric view of an end of a panel with asegment of the panel having been partially cut.

FIG. 75 is a fragmentary isometric similar to FIG. 74 with the partiallycut segment of the panel having been compressed and positioned forreceipt of an elongated clip.

FIG. 76 is a fragmentary isometric similar to FIGS. 74 and 75 showingthe clip having been mounted on the compressed segment of the panel.

FIG. 77 is a fragmentary isometric similar to FIG. 76 wherein the clipmounted on the compressed segment of the panel is being folded upwardly.

FIG. 78 is a fragmentary isometric similar to FIG. 77 wherein the clipmounted on the compressed segment of the panel has been folded90.quadrature. into abutment with the new end of the panel.

FIG. 79 is an enlarged fragmentary section taken along line 79-79 ofFIG. 78.

FIG. 80 is a fragmentary isometric view of an alternative arrangement ofa ceiling system wherein panels are suspended from rather than supportedby a supporting gridwork.

FIG. 81 is an isometric view of a panel for use in the ceiling systemshown in FIG. 80.

FIG. 82 is a fragmentary isometric view of an end of a clip member usedin the panel of FIG. 81.

FIG. 83 is a fragmentary isometric view of the clip of FIG. 82 mountedon the longitudinal end of the panel shown in FIG. 81.

FIG. 84 is an enlarged fragmentary longitudinal section taken along line84-84 of FIG. 80.

FIG. 85 is an enlarged fragmentary sectional taken along line 85-85 ofFIG. 80.

FIG. 86 is a fragmentary vertical section similar to FIG. 85 with theconventional acoustical tiles removed from their supported relationshipto the support members.

FIG. 87 is a fragmentary transverse vertical section taken through thepanel of FIG. 81 showing the outer sheet extended from a longitudinalside edge of the panel.

FIG. 88 is a fragmentary vertical section similar to FIG. 87 with theextended outer sheet being folded up and adhesively secured to alongitudinal end of the panel of FIG. 81.

FIG. 89 is a fragmentary vertical section similar to FIG. 88 with thepanel slightly compressed.

FIG. 90 is a fragmentary vertical section similar to FIG. 89 with thepanel further compressed.

FIG. 91 is a fragmentary vertical section similar to FIG. 90 with thepanel substantially fully compressed.

FIG. 92 is a fragmentary longitudinal vertical section showing the outersheet extending longitudinally from one end of the panel of FIG. 81.

FIG. 93 is a longitudinal fragmentary vertical section similar to FIG.92 with a stiffener strip supported on the outer sheet extension.

FIG. 94 is a longitudinal fragmentary vertical section similar to FIG.93 with a clip secured to the outer sheet extension.

FIG. 95 is a longitudinal fragmentary vertical section similar to FIG.94 with the clip being folded upwardly to overlie the longitudinal endof the panel.

FIGS. 92A-95A are views identical to FIGS. 92-95, respectively, showingan alternative system for mounting a clip to the end of a panel with theend of the panel being compressed in a manner to replace the stiffenerstrip used in FIGS. 92-95.

FIG. 96 is an enlarged fragmentary transverse vertical section takenalong line 96-96 of FIG. 81.

FIG. 97 is a transverse section with portions removed showing onedivider being removed to facilitate a folding of the panel.

FIG. 98 is a transverse section with portions removed similar to FIG. 97showing the panel folded about the space where the divider was removedas seen in FIG. 97.

FIG. 99 is a graph illustrating acoustical comparisons between a panelin accordance with the present invention and other panels.

FIG. 100 is a fragmentary section taken through an alternativeembodiment of a compressed panel showing a unique system for gluing thecellular structures to the outer and cover sheets.

FIG. 101 is a fragmentary section similar to FIG. 100 with the panelfully expanded.

FIG. 102 is a fragmentary isometric showing an alternative clipembodiment connected to the end of a panel.

FIG. 103 is an enlarged fragmentary section taken along line 103-103 ofFIG. 102.

FIG. 104 is a fragmentary isometric showing the clip being moved into aclosed position at the end of the associated panel.

FIG. 105 is a fragmentary vertical section showing a panel with a clipof the type shown in FIG. 102 supporting adjacent panels from aninverted T-grid support system.

FIG. 106-108 are fragmentary vertical sections showing sequential stepsfor mounting the panel with a clip of the type shown in FIG. 102 to aninverted T-grid support system.

FIG. 109 is a fragmentary vertical section with parts removedillustrating a U-shaped support system and panels with side edge clipsfor cooperation therewith.

FIG. 110 is a fragmentary vertical section similar to FIG. 109 showing adeeper U-shaped support system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The compressible structural panel 50 of the present invention isprobably best shown in FIGS. 1 and 12 to include a plurality ofcompressible preferably parallel dividers or beams 52 extending betweenan outer sheet 54 (not seen in FIG. 1) and a connector sheet 56. Adecorative sheet 58, as seen in FIGS. 1 and 12, may be provided tooverlie in face-to-face relationship the outer sheet 54. As will beexplained in more detail later, the panel is compressible from itsnormal expanded condition shown in FIGS. 1 and 12 to a fully compressedcondition as shown in FIG. 17. The panel is also bendable in onetransverse direction, as will be described in more detail later, but canbe rigidified to inhibit bending in any direction. The panel is furthercomprised mostly of air and is, therefore, very light and easy tohandle.

The panel 50 has many possible uses in building structures, such as, forexample, it might be used as a wall panel, fixed ceiling panel, aspanels for a drop ceiling, or the like. It will also be appreciated fromthe description that follows that the panels could be made of differentsizes some of which might be inordinately large in comparison toconventional panels used in building structures. For purposes of thepresent disclosure, however, the panel is illustrated of conventionalsize and for use in a drop ceiling as shown in FIG. 2.

In a typical drop ceiling system, a gridwork of elongated invertedT-shaped support members 60, as seen in FIGS. 2 and 3, areconventionally supported from a ceiling thereby defining rectangularopenings 62 and peripheral support edges 64 around those openings onwhich a ceiling tile or panel 50 can be positioned. Traditional ceilingpanels, not being bendable or otherwise pliable, are difficult to insertinto the rectangular openings 62 and due to the fact that they are alsobrittle, they are many times damaged or broken when being inserted. Thepanel of the present invention, as will be appreciated with thedescription that follows, is inherently bendable so as to facilitate itsinsertion into the rectangular opening of a drop ceiling system and oncein place will resume a desired flat planar orientation.

As probably best seen in FIG. 12, the dividers 52 are formed fromindividual strips 66 (FIG. 4) of material which have been pre-creasedand folded into a desired configuration so that when incorporated intothe panel 50 are transversely compressible allowing the panel to becompressed if desired. The dividers are secured along top portionsthereof to the connector sheet 56 and along bottom portions thereof tothe outer sheet 54 with the connections desirably being made withadhesive 68, but other systems for connecting the components would beevident to those skilled in the art. The outer sheet is, in turn,adhesively or otherwise secured in face-to-face relationship to thedecorative sheet 58, which is the sheet that is exposed to the interiorof the building structure in which the panel is incorporated. A sheetmay be defined as one or more pieces of material interlocked, bonded,welded, or otherwise joined to define a broad expansive surface. Thedecorative sheet could be any material such as real or synthetic wood,vinyl, patterned or contoured paper, foil, polyester, other syntheticmaterial, fabric, non-woven, or the like. Of course, this material wouldnormally be selected for the desired decor of the room in which theceiling panel is being incorporated but might also be selected for itsacoustical properties.

In the disclosed embodiment, the outer sheet 54, the connector sheet 56and the dividers 52 may be, but would not necessarily be, made from thesame material. That material might be a fiberglass sheet composed ofrandomly oriented glass fibers bonded together in a resin. As will beexplained in more detail later, the resin could be a thermosetting resinor a thermoplastic resin depending upon the desired characteristics ofthe panel. The adhesive 68 used to join the various components of thepanel might typically be a thermosetting adhesive, which bonds theadjacent components upon attaining a predetermined temperature.Illustrations or examples of suitable adhesives would includepolyurethane resins, copolyester hot melts, hot melt polyurethanereactive adhesives, two part epoxies, two part urethanes and RTVsilicones.

The dividers 52, as best illustrated in cross-section in FIG. 12, might,in combination, be formed from one continuous strip of material but inthe disclosed embodiment are each individual dividers of an elongatedcellular or tubular configuration. Each divider is formed from the strip66 of material such as fiberglass in a manner as shown in FIGS. 4-11.The strip material could be any color which is the same as or differentfrom the color of the connector sheet 56, decorative sheet 58, or outersheet 54.

In FIG. 4, a front view of the flat strip 66 is illustrated before it ispassed into a creaser. In the creaser, as seen in FIG. 5, the materialis passed between rotary creasing wheels 70 and back up rollers 72 sothat longitudinally extending creases 74 are formed in the material atpredetermined laterally spaced locations. In the preferred system, thecreasing wheels have an arcuate creasing edge approximately 1/32 inch indiameter and the back-up rollers are of 90-durometer hardness. With thisapparatus, an efficient fold line is created without cutting thematerial or at least without damaging many, if any, of the glass fibersso that a spring force is retained in the material. As will beappreciated, starting at the left of the strip of material as shown inFIG. 5, a crease 74 a is placed near the left edge in the top surfaceand another crease 74 b is placed in the top surface at a locationspaced slightly to the left of center. Between these two locations acrease 74 c is placed in the bottom surface of the strip. Correspondingcreases are placed on the right side of the strip so that the strip uponexiting the creaser has six creases formed therein as illustrated inFIG. 6. The strip 66 of material is then folded over and along thelongitudinal creases as illustrated in FIGS. 7, 8 and 8A bringing theside edges 76 of the strip together at a centered location on the top ofthe divider 52. Preferably, the breaking diameter of the fibers in thematerial is less than the combined thickness of the folded material sothat minimal, if any, damage occurs to the fibers during folding. Inother words, the fibers in the material will not break when the materialis folded upon itself. When so formed, the divider forms an elongatedtube or cell comprised of two truncated triangles 78 and 80 that areinverted relative to each other. The lower triangle 78 has a broaderbase than the upper triangle 80. The fiberglass material from which thedivider is made is semi-rigid so that it can be flexed and folded alongcrease lines 74 but remains substantially flat between such folds.Applying pressure to the cell as configured in FIG. 7 in a verticaldirection causes the components of the cell to compress so that thedivider assumes a compressed configuration as shown in FIG. 8. In thecompressed configuration, the adhesive 68 can be applied across the topand bottom of the divider with the adhesive preferably being athermosetting or thermoplastic adhesive applied in any of variousdifferent ways, which would be readily known to those skilled in theart.

As seen in FIG. 10, the divider 52 with adhesive 68 applied to its upperand lower faces is then passed between the outer sheet 54 and theconnector sheet 56 and as seen in FIG. 11, the entire laminate is thencompressed between heated plates 82 which activate the adhesive 68 inthe case of thermoplastic adhesives or act as a catalyst in the case ofthermosetting adhesives. Subsequent heat may be used to increase thecuring rate of a thermosetting adhesive if selected.

If a thermosetting resin is used in bonding the glass fibers within thestrips 66 and sheets 54 and 56 of material, the panel 50 will naturallyexpand to its preformed condition, as shown in FIG. 12, after havingbeen compressed and bonded together. If the resin bonding the glassfibers is a thermoplastic resin, it will remain compressed but need onlybe reheated and the strips will inherently expand under the heat, whichmight be applied, for example, with a hair dryer. Under anycircumstance, the panel can either inherently expand or be selectivelyexpanded to a desired height or thickness.

While it would be evident to one skilled in the art to modify thematerial from which the dividers 52, outer sheet 54 and connector sheet56 are made, and in fact they could each be made of different materials,for purposes of the present disclosure, the following materials havebeen found satisfactory for each of the outer and connector sheets aswell as the dividers:

JM type 8802-100GSM (Glass Mat with thermoplastic resin) or JM typeMF5020GSM (Glass Matt with thermosetting resin), each made byJohns-Manville Corp. of Denver, Colo.; or Ahlstrom type 51 50 GSM (GlassTissue with thermosetting resin) made by Ahistrom of Karhula, Finland.

There are other materials that might work well, for example, for theouter sheet or the connector sheet but not for the dividers and,conversely, there are some materials that might work well for thedividers but not for the outer and connector sheets. For example, theouter and connector sheets could be one of many different sheet types ofmaterial, such as paper, cardboard, metal, plastic, polyester, othersynthetic material, or the like. It does not even need to havestructural stability as such stability is given to the panel by thedividers. The dividers, on the other hand, while preferably being madeof fiberglass, could be made of a carbon fiber mat, some papers,cardboards, woven materials, films, or combinations thereof, with theimportant feature being that they have some predetermined modulus ofresiliency, similar to the specific materials identified above, whichallows them to be folded but remain resilient. If the materials are tobe creased to define fold lines as discussed above in connection withfiberglass material, it is important that the material retain themodulus of resiliency after having been creased, which, of course, istrue with fiberglass or carbon fiber materials.

As seen in FIG. 13, the decorative sheet 58 could also be positionedbetween the outer sheet 54 and the heat press 82 with a suitableadhesive 66 therebetween to bond the decorative sheet in face-to-facerelationship to the outer sheet. The resulting panel, of course, isillustrated in FIG. 12. When bonding the decorative sheet to the outersheet, in addition to the alternatives mentioned above, a porousdecorative sheet can be used which is bonded to the outer sheet withadhesive in a grid or printed dot pattern. This would allow thelamination to more freely pass or transmit sound therethrough.Conversely, if a continuous layer of adhesive were used to join thedecorative sheet and the outer sheet, the transmission of sound throughthe laminate would be decreased. Through the lamination process, arelatively unstable decorative sheet can be rendered flat and stablewith the resultant flat surface possibly also providing impact andpuncture resistance superceding that of the outer sheet. It will beappreciated that the acoustics of the panel can be changed by varyingthe outer sheet material, the strip material, the adhesive, theconnector sheet, the spacing between the sheets, the manner in which theassembly is joined together, or the like.

Other materials could cover or be laminated to the connector sheet 56 aswell. For example, films could be applied over the connector sheet or anadditional sheet of non-fiberglass material laminated thereto. The panelin such case could be handled without gloves in that fiberglass can beabrasive and otherwise harmful to exposed skin. Further, the film orlaminate for the connector sheet 56 could be printed with amanufacturer's identification or with a measuring grid to facilitatecutting the panel to desired sizes. Further, and as mentioned previouslywith regard to the outer sheet 54, porous laminates or films could alsobe overlaid onto the connector sheet for acoustical purposes.

As mentioned, numerous materials might have applicability in the presentinvention, but in a first preferred mode, the connector sheet and thedividers are made of the same material, which is a fiberglass mat madeby Johns-Manville Corporation and the mat may be one designated No. 5802or one designated No. 5803 by Johns-Manville. The 5802 is a 120g/m.sup.2 mat composed of 10% PET/65% 16-micron glass/25% MF. The 5803is a 100 g/m.sup.2 mat composed of 12% PET/68% 16-micron glass/20% MF.MF is an abbreviation for melamine formaldehyde resin, which exhibitsthe characteristics of a thermoset resin. PET is an abbreviation for apolyethylene terephthalate. Dividers made from either of the 5802 or5803 material have the ability to expand with little or no addition ofheat after having been creased and folded as described previously andafter having been fully compressed. A more complete description of theJohns-Manville products and related products can be found in U.S. Pat.Nos. 5,840,413, 5,942,288, and 5,972,434, which are herein incorporatedby reference.

The preferred outer sheet for the first preferred mode is a compositelamination of an aesthetically pleasing textile material, which has beenlaminated to a glass non-woven base using a co-polyester hot-meltadhesive. Several such laminates can be equally desirable. The firstsuch laminate utilizes an aesthetically pleasing textile material in thenature of a thermal bond polyester non-woven having a basis weight inthe range of 45 to 75 g/m.sup.2 and can be purchased from Hollingsworthand Vose of Floyd, West Va. The adhesive pattern used to thermally bondthe polyester fibers in the non-woven material becomes the visualpattern upon the bottom surface of the outer sheet. When a smallpoint-bonding pattern with a bonding area of approximately 7% is used,the preferred polyester non-woven textile material is one designated byHollingsworth and Vose as TR2315A-B. When a large point-bonding patternis used, approximately 21% bonding area, the preferred textile materialis designated TR2864C1 by Hollingsworth and Vose. Either non-wovenaesthetically pleasing textile material is then screen coated using anacrylic binder/flame retardant coating with an additional weight of 15to 25 g/m2. The coating can be formulated to increase the durability ofthe non-woven aesthetically pleasing textile material while adding flameretardant. The polyester non-woven textile material can then be runthrough a hot-melt roll coater/laminator where a flame resistantco-polyester adhesive from, for example, EMS Chemie North America ofSumter, N.C., is applied to the surface of either the polyesternon-woven textile material or the glass non-woven base material to becoated thereon. The coating weight of this adhesive is dependent uponthe bond strength desired to achieve between the polyester non-woventextile material and the glass non-woven base material. Generally anadhesive having a basis weight in the range of 30 to 45 g/m.sup.2 hasbeen found desirable. A Gravure roller, preferably having a crosshatch25.times.25 pattern thereon is used to compressively laminate the glassnon-woven base to the polyester non-woven aesthetically pleasing textilematerial. The depth of the engraving on the Gravure roller is a mainvariable related to the adhesive weight per area being applied. Theadhesive formulation obtained from EMS Chemie is a 50:50 mix of twomaterials with the materials designated by EMS as Grilltex D1573G andGrilltex VP1692G. The EMS Grilltex VP1692G is compounded with a 25%loading of an organic phosphorous flame retardant. The resulting 50:50mix produces a final flame-retardant loading of approximately 13.5%.Following the application of the adhesive upon the surface of thepolyester non-woven material, the adhesive is kept molten until it isjoined with the glass non-woven base material. The glass non-woven basematerial is preferably the afore-noted 5802 (120 g/m.sup.2) matting soldby Johns-Manville, a glass non-woven from Ahlstrom designatedGFT-413G10-60-1300 (60 g/m.sup.2) or a non-woven glass matting fromAhistrom designated GFT-413G10-80-1300 (80 g/m.sup.2). A compositelaminate made with the above-noted materials is inherently translucentand that feature combined with the ability of light to travel down thelength of the cells defined between the dividers in a finished panelmakes it possible to see shadows in the areas where two cells meet.

The shadowing can be decreased if desired, by using, in lieu of theafore-noted polyester non-woven textile material, an aesthetic materialhaving a silver, gray, or black color upon its back side. The backsideis the one, which receives the hot-melt adhesive and is subsequentlylaminated to the glass non-woven base matting. The coloring reduces theamount of light which can travel down the cells and up through thesurface thus reducing the shadowing effect. 5% carbon black in theaesthetic material has proven to provide desirable results.

An alternative aesthetic textile material to the polyester non-wovendescribed above is a knit material, which has a silver, gray, or blackappearance on one side. To achieve this, a knit material from Gilfordtechnical textiles of Greensboro, N.C., has been used with the knitmaterial being composed of two different types of yarns in a single knitconstruction. The preferred yarns used are nylon and polyester. Thenylon yarns are mainly observed on one side of the matting and thepolyester on the other. The knitted material is “cross-dyed” with blackdyestuffs that have affinity for the nylon and leaving the polyesterwhite in color. A flame retardant and soil release may also be added tothe dye bath formulation. The knit is then stabilized and a melamineresin added to stiffen the fabric. The knit material can then belaminated to the glass non-woven base material as previously describedwith the polyester fiber material. The preferred Gravure roller patternused in this case is one having a random computerized dot pattern andwhich is well known in the trade. When the silver, gray, or black sideof the knit is laminated to the glass non-woven base material, the lighttransmittance through the laminate is reduced by the presence of thedarker layer. The visual appearance of the surface is unique in that itmimics the appearance of a perforated metal ceiling panel. You can alsolaminate the white side of the knit material to the glass non-wovenmaterial and when doing so, the appearance of the knit lamination mimicsa metal screen material but also eliminates the shadowing effect.

Another method of reducing reflected light and transmitted lightshadowing is the use of a colored black, gray, or silver glass non-wovenbase material. If the pigmented black, gray, or silver glass non-wovenis laminated to either the polyester fiber mat or the knit mattingdescribed previously, the shadowing effect can also be reduced.

It should also be noted that the coloring of the aesthetic material,whether it be the polyester fiber matting or the knit material, could beobtained by printing or coating the materials with a colored pigment.This would involve a secondary printing or coating step, which would addto the cost. The use of colored or pigmented adhesive may also beemployed as a low-cost solution to the shadowing and/or increasedsurface whiteness of the aesthetic material.

Still a further system for reducing or eliminating shadowing is to makethe dividers 52 a gray color such as by making the divider from amaterial with 0.03% carbon black.

Through experimentation, the flame resistancy of a panel formed inaccordance with the present invention can be improved by using MelamineFormaldehyde exclusively as the binder for the glass fibers in both theouter sheet and the connector sheet in the panel. In other words, therewould be no thermoplastic resin utilized in the outer sheet or connectorsheet, and since the Melamine Formaldehyde does not burn, there is someimprovement in the flame resistancy of the panel. A core for such apanel in which improvement is desired for the flame resistancy couldstill be made from the John's Manville fiberglass matting designated No.5802 but the adhesive used to bond the dividers to the outer sheet andconnector sheets would be made with no fire resistant additives so thatthe glue burned quickly and would smoke for a shorter time period. Theadhesive used in the outer sheet between the decorative layer and theunderlying base layer would desirably have fire resistant properties.

In a second preferred embodiment of the invention, the decorative layermaterial would not change from that described previously, but the outerlayer, connector layer and dividers would be made of materials that donot use Melamine Formaldehyde as the Melamine Formaldehyde can producetoxic gases if the panels are subjected to high temperatures that affectcomplete decomposition of all organic materials. In this secondpreferred embodiment, the outer layer would be made of a 120 g/m.sup.2(gsm) glass matte composed of 85% 13 micron glass fibers bound with 15%PAA binder. PAA is an acronym for Poly Acrylic Acid, which may becategorized as a thermoset resin. Such a glass matte material isavailable from Johns Manville of Denver, Colo., and designated R8235glass matting. The connector sheet could be either a 13 micron or 16micron glass matte, which is also 120 μm composed of 85% glass fiber and15% PAA binder. Accordingly, the connector sheet could be made from thesame Johns Manville R8235 material or a similar material where the glassfibers were 16 micron rather than 13 micron. The dividers are made froma material that is a 120 μm glass matte composed of 70% 16 micron glassfibers bound with 20% PAA and 10% PET (polyester fibers). The dividermaterial can also be obtained from Johns Manville under R8221 glassmatting.

FIGS. 14-17 illustrate the assembled panel 50 in progressivelycompressed conditions with FIG. 14 showing the panel in a fully expandedcondition and FIG. 17 in a fully collapsed or compressed condition.

An isometric view of the panel 50 is shown in FIG. 18 and an enlargementthereof in FIG. 19. It will there be readily appreciated that thedividers 52 are evenly spaced from each other while extending parallelto each other and longitudinally of the panel. Of course, in FIGS. 18and 19, the panel is fully expanded with the panel being shown fullycompressed in corresponding views 20 and 21, respectively.

A problem with conventional ceiling panels is that they remain of thesame size and thickness during shipment, installation and use. Adesirable feature of the panel of the present invention resides in thefact that, while the panel has a predetermined at rest or expandedthickness that might correspond with that of conventional ceilingpanels, it can be compressed for shipping purposes so that far morepanels can be packed in one container for shipping purposes therebyimproving shipping costs considerably. When the panels are removed fromthe shipping container, they will either naturally expand if athermosetting resin was used in the fiberglass material or can be heatedto expand if a thermoplastic resin was used. While the panel could beexpanded to any predetermined desired thickness, a preferred panel forceilings might be in the range of 12 to 26 mm in thickness whendesirably expanded depending on the span of the panel but could bethicker or thinner depending on use, and approximately 3-4 mm inthickness when fully compressed.

As best seen in FIG. 31, the panel 50 can easily be flexed or benttransversely of the direction in which the elongated dividers 52 extendto facilitate the insertion of the panel into the support structure of adrop ceiling, for example. In fact, the panel can be preformed in thebent configuration so that this becomes its at rest configuration shoulda curved panel be desired for some reason. The panel will not flex orbend very easily in the opposite direction, i.e. the direction in whichthe dividers extend, as the tubular configurations of the dividers willinhibit such. If desired, however, the panel can be substantiallyrigidified so that it is inhibited from bending in either transversedirection by placing support members 84 along opposite ends of the panelso as to cover the open ends 86 of the tubular or cellular dividers. Thesupport members 84 can either be preformed C-shaped channel members 88(such as plastic, aluminum, etc.) of a rigid configuration, asillustrated in FIGS. 24 and 25, or can be strips 90 of adhesivematerial, for example, which are adhered to the ends of the panel asillustrated in FIG. 26. While the strips of adhesive material would havesome flexibility, it would have enough stiffness so that whenincorporated onto the ends of the panel, it will inherently prevent thepanel from bending in a transverse direction relative to thelongitudinal direction of the dividers. Plastic or vinyl tapes or thelike would be an illustration of a suitable adhesive strip. As a furtheralternative and as shown in FIGS. 65-67, a divider 52 a could be placedat each end of the panel to cover the open ends of the parallel dividers52. The outer sheet 54 and connector sheet 56 are extended to cover thedividers 52 a which serve to rigidify the panel in the cross direction.

The panel can also be rigidified in a cross-direction by incorporatingcross dividers (not shown) at selected locations throughout the panel.The cross dividers would run perpendicularly to the primary dividers andmight assume an identical or varied configuration to the cross-sectionalconfiguration of the primary dividers. Of course, the cross dividerscould be adhesively bonded in the panel the same as the primarydividers. The height of the dividers, whether they be primary dividersor cross dividers, can also be varied across the width of a panel tocreate varied structural and aesthetic effects.

To change the structural characteristics of the dividers 52, the outeror inner surface of the divider can also be laminated with another sheetof material and possibly a metallic sheet material 92, which renders thedivider material slightly more rigid, as illustrated in FIGS. 28 and 27,respectively. A metallic sheet would also affect the thermalcharacteristics of the panel. FIG. 27 shows the metallic sheet materialon a panel with a support member 88 while FIG. 28 does not include asupport member. Of course, the lamination process would take placeduring the formation of the divider and preferably immediately beforecreasing.

As seen in FIGS. 29 and 30, the panel formed in accordance with theabove process is unique in that pressure applied at any one location toone surface of the panel will only depress the panel at that locationand will not deform the opposite side of the panel. The panel will alsosupport multiples of its own weight without deflection on the oppositeside of the panel. By way of example, a panel formed in accordance withthe present invention that is 26 millimeters thick when expanded andwhich is 24 inches wide by 48 inches long weighs approximately 0.9kilograms (1.98 pounds). The panel can support up to 2.9 kilograms load(6.38 pounds) in the form of a circular weight 10 inches in diameterwith minimal deflection observed on the opposite side of the panel.Point loads of approximately 2 inches in diameter and weighing 1kilogram (2.2 pounds) are also easily absorbed by the same panel with nodeflection of the bottom surface.

With reference to FIGS. 33-35, a second embodiment of a panel 94 isillustrated wherein the connector sheet 54 has been replaced with aconnector in the form of a plurality of elongated flexible butnon-extensible strands or fibers 96. These strands or fibers could beplastic, nylon or other similar material having the same or similarcharacteristics. The strands or fibers of material can be adhesively orotherwise bonded to tubular dividers 52′ while extending transverselythereto and with the fibers spaced from each other preferably inparallel relationship to each other. A panel 94 so formed can be easilyflexed or bent, as illustrated in FIG. 35, in a direction transverse tothe longitudinal direction of the dividers as with the previouslydescribed panel.

In each of the afore-described embodiments of the invention, thedividers have identical side partitions 98 (FIGS. 12 and 34) which havelongitudinal fold lines 100 therein so that the side partitions foldinwardly when the panel is compressed. The side partitions therebydefine upper and lower portions 98 a and 98 b, respectively, which arerectangular in configuration but wherein the upper portion 98 a is of asmaller dimension than the lower portion 98 b. This arrangement might bereferred to as an asymmetric arrangement in that the upper portion ofthe divider is of a different size than the lower portion.

A third embodiment of the present invention is illustrated in FIGS.36-42 and in this embodiment, a panel 102 is identical to that shown inFIG. 12 except that the partitions 104 in the dividers 105 are symmetricin configuration. In other words, the panel 102 includes an outer sheet54′ and a connector sheet 56′ interconnected by dividers with partitionsand may include a decorative panel 58′ overlying the outer sheet ifdesired. Fold lines 106 along the partitions 104, however, arepositioned so that an upper rectangular portion 104 a of each partitionis of equal size to a lower rectangular portion 104 b. The panel 102 canagain be compressed.

The compressed and expanded forms of the panel 102 shown in FIGS. 36-38are illustrated isometrically in FIGS. 39 and 40 and it will beappreciated that the panel can be fully compressed to a depth or sideprofile that is far less than its normal expanded condition.

As seen in FIGS. 41 and 42, when the panels are stacked, a considerableamount of space can be saved by compressing the panels, which, ofcourse, saves considerable expense when shipping as, more panels can becompressed and shipped in one container than with conventional ceilingpanels.

An advantage of a panel using symmetric dividers resides in theelimination of telegraphing that can, if not carefully watched, exist incompressed panels. Telegraphing is a phenomenon that can result incompressed panels of the type described herein when a sheet iscompressed tightly against other components of the panel such asdividers or partitions. If the pressure is too great or the dividersexert too much resistance, a visual pattern can be seen through thesheet where a partition is secured thereto and where it is not.

By reference to FIG. 17, which illustrates a panel with asymmetricdividers, it will be appreciated there are spaces between the dividersalong their connections to the connector sheet, but such a gap hardlyexists when using symmetric dividers as best seen in FIG. 38.Accordingly, in a panel using symmetric dividers as shown in FIG. 38,telegraphing is virtually eliminated regardless of the pressure appliedto the panel. It should also be appreciated, however, that in panels ofthe present invention with symmetric or asymmetric dividers, there isless tendency for telegraphing due to the fact that when the connectorsheet is forced downwardly against the dividers, they do not resist thepressure but simply compress so that an adequate pressure for bondingthe connector sheet to the dividers can be applied without creatingtelegraphing.

By changing the location of the fold line 106 in each side partition ofa divider 105, the resistance of the panel to compression can also beregulated. For example, in the at rest expanded position of anasymmetric panel 50 such as disclosed as the first embodiment of thepresent invention and shown in FIGS. 43 and 45, an obtuse angle “a” isformed in the side partition 98 which is greater than the correspondingangle “d” in the partition 104 as shown in FIG. 46 of a symmetric panel.The height A of each panel in the expanded form is, however, identical.Note also the difference in the length B and C of the upper and lowerportions 98 a and 98 b, respectively, of the side partitions of theasymmetric divider, whereas in the symmetric divider illustrated in FIG.46, the length D of the upper partition portion 104 a and the lowerpartition portion 104 b are identical.

The greater the angle “a” or “d” in the side partition, the moreresistance there will be to compressing the panel, as illustrated inFIGS. 47 and 48. In FIGS. 47 and 48, an equal force F is shown beingapplied to the asymmetric divider panel 50 in FIG. 47 and the symmetricdivider panel 102 in FIG. 48 and it will be seen that the same amount offorce compresses the symmetric divider panel a greater amount. This isbecause the angle in the side partition in the symmetric divider panelis smaller than the angle in the asymmetric divider panel.

By way of illustration and not limitation, in a panel formed inaccordance with the present invention which has been found to providesatisfactory performance and wherein the outer sheet, connector sheetand dividers are all made of 100GSM Johns Manville #8802 glass matting,the parameters identified in FIGS. 43 through 46 fall in the followingranges:

X=5 to 10 mm

S=20 to 40 mm

A=15 to 26 mm

B=8 to 10 mm

C=13.5 to 17 mm

D=13.5 to 15 mm

a=100 to 120 degrees

b=100 to 120 degrees

In another alternative embodiment 108 of a panel in accordance with thepresent invention shown in FIGS. 51 and 52, the connector sheet of thepreviously described embodiments is eliminated by the use of a uniquedivider 110. The divider 110, as best seen in FIGS. 49 and 50, is ofgenerally hourglass configuration defining two truncated triangularzones 112 and 114 inverted relative to each other similarly to the firstdescribed embodiment of the present invention, but the top of thedivider has a long horizontal leg adapted to overlap an adjacent dividerso as to have a segmented connector sheet 116 that is composed of aplurality of interconnected strips defined by the horizontal top leg ofthe divider. While the divider 110 has been shown to be asymmetric, itcould, in fact, assume a symmetric configuration similar to that shownin the third described embodiment of the present invention. The divider,therefore, has a base 118, a left side partition 120 and a right sidepartition 122, with each side partition having a horizontal leg 124 and126 respectively at its top. Both of the side partitions have a creaseline 128 so that the side partitions will fold when pressure is appliedto the top or bottom of the divider. The horizontal top leg 126 of theright side partition is approximately a third of the width of thedivider at its top, but the horizontal leg 124 from the left sidedivider is slightly longer than the base 118 of the divider so that itoverlies and overlaps the horizontal top leg 122 of the right divider.

As is best seen in FIG. 51, when a plurality of the dividers 110 arepositioned in immediately adjacent or contiguous side-by-siderelationship, the top horizontal leg 124 from the left side partition120 extends beyond the right side partition 122 and into overlappingrelationship with the top horizontal leg 124 of the left side partition120 of the next adjacent partition to the right. The overlappinghorizontal top legs 124 from the left side partitions thereby form incombination a segmented but integrated connector sheet. Of course, thetop horizontal leg 124 from the left side partitions of each divider isadhesively secured to the top horizontal leg 126 from the right sidepartition and also to the top horizontal leg 124 from the left sidepartition of the divider that is to the immediate right thereof. A coversheet 130 is secured to the base 118 of each of the dividers tointerconnect the dividers along their bases and, of course, a decorativesheet (not shown) can be secured to the lower face of the outer sheet orthe segmented connector sheet if desired.

Still another embodiment 132 of a panel formed in accordance with thepresent invention is shown in FIGS. 53-55, and in this embodiment, thedividers 134 are not cellular in and of themselves but are rather stripsof material that have been folded into a zig-zag pattern and securedbetween an outer sheet 136 and a connector sheet 138 so as to form acellular compressible panel. Looking initially at FIGS. 53 and 54, thedivider 134 is formed from a strip of material which has a pair of outerparallel crease lines 140 and inner parallel crease lines 142 but withthe outer crease lines being folded in opposite directions and the innercrease lines being folded in opposite directions. A pair of attachmentsurfaces or marginal zones 144 and 146 are thereby defined between theouter crease lines 140 and the side edges 148 of the strip which can besecured in any suitable manner to the outer sheet and the connectorsheet respectively. In between these marginal zones of the dividers, anintermediate portion 150 of the divider has the two inner folds thereinallowing the strip to fold when transverse pressure is applied to eitherof the marginal zones. The panel 132 formed with the dividers 134 ofFIGS. 53 and 54 is shown in FIGS. 55 and 56 in an expanded andcompressed condition, respectively.

Another divider 152 is shown in FIGS. 57 and 58 for use in a panel 154shown in FIGS. 59 and 60 in an expanded and collapsed condition,respectively. The divider 152, as seen in FIGS. 57 and 58, includes apair of parallel outer crease lines 156 with folds in the same directiontherein spaced inwardly from the side edges 158 of a strip of materialfrom which the divider is formed and a third intermediate crease line160 between the parallel outer crease lines. An upper marginal zone 162is defined between one edge of the strip of material and one of theouter crease lines and a second much larger lower marginal zone 164 isdefined along the bottom of the divider between the associated edge ofthe strip of material and the adjacent crease line. A fold in anopposite direction is provided at the intermediate crease line 160 sothat the divider has upper and lower marginal zones of different widthsthat both project to the right, as viewed in FIG. 8, from their adjacentfold lines 156. The upper marginal zone 162 of each divider is securedto a connector sheet 166 at parallel equally spaced locations while thelower marginal zones 164 are adapted to extend to the right and overlapa small portion of the next adjacent divider to the right. Theoverlapping lower marginal zones are secured to each other therebyforming an integrated segmented outer sheet 168 formed from theplurality of lower marginal zones of the respective dividers. Of course,a decorative sheet (not shown) could overlie the interconnected lowermarginal zones or the connector sheet to provide variety to theaesthetics of the panel.

A similar embodiment 170 of a divider is shown in FIGS. 61-64 where,again, a strip of material is provided with a pair of outer crease lines172 and an intermediate crease line 174 therebetween, with upper andlower marginal zones 176 and 178 being defined between the edges 180 ofthe strip and the outer crease lines 172. The folds at the outer creaselines 172 are in an opposite direction to the fold along theintermediate crease line 174 so that the outer and lower marginal zonesboth project horizontally to the right, as viewed in FIG. 62. As will beappreciated, both of the horizontal zones extend horizontally beyond theintermediate crease line 174 and are adapted to overlap the upper andlower marginal zones of adjacent dividers to the right so that they canbe secured thereto in any suitable manner to form the panel shownexpanded in FIG. 63 and compressed in FIG. 64.

In a further embodiment of a panel 182 made in accordance with theteachings of the present invention, and as seen in FIGS. 68-73, thepanel again has an outer sheet 54, a connector sheet 56 and a pluralityof dividers 184 extending therebetween. As is probably best seen inFIGS. 68 and 71, the dividers 184 a in a part of the panel are ofZ-shaped cross-section while the dividers 184 b in the other part of thepanel are of reverse Z-shaped cross-section. At the location 186 atwhich the direction of the dividers changes, the panel can be bent at aright angle as seen in FIGS. 72 and 73 so that the panel can, forexample, follow the right-angled contours of building components onwhich it is mounted. For example, the panel could be wrapped aroundrectangular ductwork of the type that might be found in a house forconducting forced air or the like.

Referring again to FIGS. 68 and 71, it will be appreciated on theright-hand portion of the panel that the dividers 184 a are Z-shaped incross-section so as to define an upper horizontal leg 188 that extendsto the left, a lower horizontal leg 190 that extends to the right and adiagonal connecting leg 192 that connects the right edge of the upperleg to the left edge of the lower leg. The Z-shaped dividers 184 a are,of course, formed similarly to those described previously by placingcrease lines in strips of material from which the dividers are made andthen folding the strips of material along the crease lines. The reverseZ-shaped dividers 184 b on the left side of the panel, of course, havean upper horizontal leg 194 that extends to the right, a lowerhorizontal leg 196 that extends to the left and a diagonal connectingleg 198 that extends from the left edge of the upper leg to the rightedge of the lower leg.

As is best seen in FIGS. 68 and 71-73, at the location 186 where thedirection of the dividers changes, (in the illustrated panel, near itscenter) the panel can be folded at a right angle. The panel can then befully expanded as shown in FIGS. 72 and 73 so that the legs of thedividers are perpendicular to each other thereby forming rectangularcells.

With reference to FIGS. 68 and 69, it will be appreciated that the panelcan also be compressed as with the earlier described embodiments ofpanels made in accordance with the present invention.

In still a further embodiment 190 of the panel of the present inventionshown in FIGS. 100 and 101, the dividers 192 are of the configurationillustrated for example in FIGS. 7-9 even though they have been invertedso that the bottom of the divider is shown on the top and secured to theoverlying outer sheet 194 along three parallel glue lines 196. Theopposite side of the divider which is open and defined by two flaps 198and 200 has one of the flaps 198 secured to the connector sheet 202while the other flap 200 is unsecured. The panel 190 is shown in acompressed condition in FIG. 100 and an expanded position in FIG. 101.In the compressed condition, it will be seen that the connector sheet202 is shifted slightly to the right relative to the outer sheet 194.When the panel is allowed to fully expand as shown in FIG. 101, the leftsidewall 204 of each cell folds out into a vertical orientation as thematerial from which the cell is made biases the sheet toward a flatorientation and in doing so, the connector sheet 202 is pulled orshifted to the left so that its edges become aligned with the edge ofthe outer sheet. The movement of the connector sheet to the left iscaused by the unfolding of the sidewalls of the divider. The connectionof the left flap 198 to the connector sheet 202 pulls the connectorsheet to the left upon expansion of the cell. On the other hand, as theright side of the dividers unfolds and assumes a vertical orientation,the bottom flap 200 associated therewith is allowed to slide relative tothe connector sheet 202 so that the flaps become more separated thanthey are in the compressed condition of FIG. 100. The right sidewall ofone divider is then folded into contiguous relationship with the leftsidewall of an adjacent divider so that the sidewalls of the dividersreinforce each other and become somewhat rigid to rigidify the panel sothat it cannot be easily compressed.

The panel of the present invention is also amenable to rigidification ina cross-direction in a manner illustrated in FIGS. 74-79. It will therebe appreciated that a segment of the panel near an end thereof can bepartially cut at 89 by cutting through the connector sheet 56 and thedividers 52 (in a direction transverse to the length of the dividers)but not severing the outer sheet 54. This cut forms a small band 91 ofmaterial, which can be independently compressed as illustrated in FIG.75 to receive a rigidifying clip 93. The rigidifying clip in thedisclosed embodiment is of substantially J-shaped cross-section having along side 95, a spaced parallel short side 97, a connecting wall 99interconnecting corresponding edges of the long and short sides and alip 101 depending from the long side along the opposite edge from theconnecting wall 99. The clip is mounted on the compressed band ofmaterial so as to retain the material in a compressed state. The clipand compressed material can then be folded upwardly as shown in FIGS. 77and 78 to form a rigidification along the end of the panel. Of course,the rigidified band of material can be adhesively secured in positionafter it has been folded upwardly as illustrated in FIGS. 78 and 79 ifdesired.

The clip, with appropriate modification readily evident to those skilledin the art, can also be used as a mounting clip for suspending the panelfrom ceiling support members (not shown) such as of the type describedin U.S. Pat. No. 6,199,337 entitled Cladding System and Panel for Use inSuch System, which is of common ownership with the present invention.That patent is hereby incorporated by reference.

It should be further understood from the above description of thevarious embodiments of the present invention that the dividers each haveunique features that could be incorporated into the other embodiments.By way of example only, the upper and lower portions of the sidepartitions of the various dividers or the upper and lower portions ofthe walls separating the upper and lower marginal zones could be of thesame or different dimensions so as to define symmetric and asymmetricdividers. Further, simply changing the angle in the side partition of adivider causes one panel to be more compressible than another.Similarly, by spacing the dividers at greater distances, the panel wouldbe more easily bendable in a transverse direction to the dividers. Thedepth of the dividers will also affect the strength of the panels(assuming other parameters remain unchanged) so that the length andwidth of a panel (i.e. the span) can be significantly enlarged withoutaltering strength or bonding characteristics of the panel simply byincreasing the depth of the dividers. Also, as mentioned previously,numerous aesthetics and acoustical properties can be created bylaminating different types of decorative sheets to the outer sheet ofthe panel so that one might create a different color, pattern, texture,or the like to the interior of the room in which the panel is used.

It will further be appreciated from the above description that thematerial from which the outer sheet, connector sheet or dividers is madecan be varied to achieve different characteristics for the panel. Forexample, the materials could be varied to obtain different acousticcharacteristics for the panel or to obtain different light transmittingcharacteristics. Also, the materials could be fire retardant to inhibitthe spread of a fire in a building in which the panels were being used.It would also be possible to utilize different materials in the panelwith for example the cover sheet or the connector sheet being made ofthe same or different materials and the dividers also being made of amaterial that is the same as or different from one of the cover orconnector sheets. The dividers themselves might be made of differentmaterials within a single panel. For example certain dividers may beprovided to obtain the resilient and compressible feature of the panelwhile other dividers might be provided to vary the acoustics, lighttransmitting or fire retardant capabilities of the panel. Also, thepanels could be stacked in a building structure to alter the acoustic orlight transmitting characteristics of the panels.

While the panels previously described have principally been describedfor use as a replacement to conventional acoustical tiles that aresupported on the T-shaped support members of a drop ceiling gridwork,the panel can be modified slightly so as to also be suspendable from thesame T-shaped support members. As will be appreciated, by suspendingpanels of the present invention from the T-shape support members 60, thepanels can be used to replace or renew an existing ceiling system withor without removing the acoustical tiles positioned or supported on topof the T-shaped support members 60.

A panel 200 that has been modified to be suspendable from or supportableby the T-shaped support members 60 is shown in FIGS. 80-96 with aplurality of the panels shown in FIG. 8 installed in underlyingrelationship to existing acoustical panels 202 supported on supportmembers 60. As will be appreciated, each panel 200 is of the generaltype previously described and as seen in FIGS. 84-86 has an outer sheet204, a connector sheet 206, and a plurality of parallel cellulardividers 208 therebetween. The cellular dividers are preferably, aspreviously described, compressible in nature and best seen in FIGS.87-91 as being formed from individual strips of material that have beencreased and folded so as to define elongated tubes having two truncatedtriangular areas 210 and 212 superimposed upon each other. The dividers208 have foldable intermediate side walls 214 with fold lines 216, whichallow the side walls to either fold inwardly as shown in FIGS. 89-91 orfold outwardly as shown in FIGS. 87 and 88 depending upon a number ofconditions including the type of binder used in the fiberglass mattingmaterial from which the dividers are made and the treatment of thedividers to heat and cold which will be described in more detail later.

At each end of the panel 200 along the open ends of the cellulardividers 208, a unique clip 218 as seen best in FIGS. 81-86, is securedto the panel. The clips are elongated and preferably extruded members ofa rigid material such as aluminum, plastic, or the like and aregenerally of inverted J-shaped configuration as probably best seen inFIG. 82. They therefore define a vertical main flat body 220 with alower protruding lip 222 from the bottom edge of the main body. An upperdownwardly opening hook-shaped channel 224 extends from the upper edgeof the main body. Also along the upper edge is formed a second orhorizontally opening hook-shaped channel 226 which protrudes from themain body in the opposite direction as the lip 222 even though it opensin the same direction as the lip 222. An obliquely protruding rib 228extends downwardly from the upper edge of the main body beneath thehorizontally opening channel 226.

With reference to FIGS. 92-95, the clip 218 is secured to the end of thepanel 200 either by notching the end of the panel, as describedpreviously, so that the outer sheet 204 protrudes longitudinally fromopposite ends of the panel or the outer sheet can be made slightlylonger and wider than the remainder of the panel so that it naturallyprotrudes from opposite ends and opposite sides as shown in FIGS. 87 and92 defining outer sheet longitudinal extensions 230 and outer sheetlateral extensions 232. An elongated straight stiffening strip 234,which might be made of plastic, aluminum, paperboard, or the like, isadhesively bonded to the top surface of the outer sheet longitudinalextension 230 where it protrudes from the ends of the panel and clipsare thereafter positioned over the outer sheet longitudinal extensionsand the stiffeners as shown in FIG. 94 by inserting the stiffener stripsand outer sheet longitudinal extensions into the downwardly openingJ-shaped channels 224 adjacent to the main bodies with the lip 222hanging over the innermost edge of the stiffeners. With the clips sopositioned, the outer sheet longitudinal extensions 230, stiffener 234and clip 218 can be folded upwardly as shown in FIG. 95 until theconnector sheet 206 at opposite ends of the panel is received betweenthe horizontally opening J-shape channels 226 and the oblique ribs 228of the clips. The underside of the horizontally opening J-shapedchannels 226 can then be adhesively or otherwise secured to theconnector sheet 206 to hold the clip in the position illustrated in FIG.95.

The oblique rib 228 of each clip projects beneath the connector sheet206 so as to hold the panel in a fully expanded position. By followingthe same procedure at each longitudinal end of the panel, it will beappreciated that the ends of each panel will have a clip thereon and thehorizontally opening J-shaped channels 226 are positioned to be securedto a flange of the T-shaped support member 60 as shown in FIGS. 84 and85.

An alternative way for securing a J-shaped clip to ends of the panel isshown in FIGS. 92A-95A. In the alternative system, at an openlongitudinal end of a panel, a cut or slit is made downwardly throughthe connector sheet 206 and the open ends of the dividers 208 as shownin FIG. 92A, so as to define a slight gap between the severed portionsof the connector sheet and the dividers and the remainder of the panel.The severed portions of the connector sheet and dividers are thencompressed downwardly into closely adjacent relationship with the outersheet 204 and this compressed material is then inserted into thedownwardly opening J-shaped channels 224 of the clip so that the lip 222of the clip hangs over the innermost edge of the compressed material, asshown in FIG. 94A. The clip with the compressed material confinedtherein is then folded upwardly as shown in FIG. 95A and secured inposition, preferably with adhesive so as to define a longitudinal end ofa panel.

As illustrated in FIG. 83, the ends of the horizontally opening J-shapedchannels 226 are spaced inwardly from opposite longitudinal ends of theclip 218 to accommodate a T-shaped support member 60 that extendsperpendicularly to the T-shaped support member 60 to which the clip issecured. In this manner, the panels can be carried by a conventionalgridwork of T-shaped support members in a suspended or supported mannerwith or without another set of acoustical tiles being supported by thegridwork. In other words, the panels 200 with the clips 218 securedthereto can be used in connection with an existing gridwork or inconnection with a new gridwork in exactly the same manner. As will alsobe appreciated, the clips of adjacent longitudinally aligned suspendedpanels can abut each other (FIG. 85) so the ends of the outer sheets ofthe panels are only slightly spaced to give a substantially continuousappearance to the ceiling with virtually no view of the gridwork fromwhich the panels are suspended. Further, due to the fact that the clipshold the panels in their fully expanded position, the lower or outersheet 204 of each panel will be horizontally aligned with the outersheet of an adjacent panel to give a smooth uniform appearance to aceiling formed from such panels. Referring to FIGS. 87-91, the outersheet lateral extensions 232 can be folded up into engagement with theadjacent sidewall 214 of the outermost divider and secured thereto witha suitable adhesive to give the panel a finished look along its sideedges. Systems for folding the lateral extensions can be found inco-pending application Ser. No. 10/309,944, filed Dec. 3, 2002, andentitled “Method and Apparatus for Fabricating Cellular StructuralPanels,” which is of common ownership with this application and ishereby incorporated by reference.

A slightly modified clip 240 for the ends of the panels 200 is shown inFIGS. 102-108. The clip 240 is substantially similar to thepreviously-described clip 218 shown in FIG. 82, the difference residingsimply in the fact that the clip 240 does not have a rib 228. Indescribing the clip 240 corresponding parts to the clip 218 will beassigned corresponding reference numerals with a prime suffix. The clip240 could be mounted on the ends of the panel in any of theafore-described ways or it could be mounted as described in theaforenoted co-pending application Ser. No. 10/309,944. In the methodshown in the afore-described pending application, the entire panel 200is compressed and clips 240 mounted on opposite ends of the panel sothat the compressed material along the ends of the panel is confinedwithin a channel 224′ adjacent to the main body 220′ of the clip.Subsequent to mounting the clip on the compressed ends of the panel, anotch is formed in the panel adjacent to the clip so that a lip 222′ onthe clip can protrude into the notch allowing the clip to be fullyreceived on the compressed end of the panel. The notch also allows theclipped ends of the panel to be folded into confronting overlyingrelationship with the open ends of the dividers as seen in FIG. 104 tothereby close the ends of the panel. The clip is shown mounted on thecompressed end of the panel in FIG. 102 where the remainder of the panelhas been allowed to expand and closed into overlying relationship withthe open ends of the dividers in FIG. 104. Another difference in theclip shown in FIGS. 102-108 and the clip 218 shown in FIG. 82 resides inthe fact that a channel 242 is defined between the downwardly openingchannel 224′ and the horizontally opening channel 226′ with the channel242 opening in the opposite direction to the channel 226′. The channel242 is provided to facilitate the mounting of a panel having the clipson the ends thereof to a supporting T-grid system as will be describedhereafter.

As best seen in FIGS. 106-108, when mounting a panel 200 having theclips 240 on the opposite ends thereof on a T-grid system whereininverted T-shape supports 241 in the system have oppositely directedflanges 244 on which other panels 246 of a ceiling system may besupported, the clip 240 on one end of the panel is advanced onto anassociated flange 244 by inserting the flange into the horizontalchannel 226′. It will be appreciated that the connector sheet 206 of thepanel, which is at the top thereof, may or may not be fully insertedinto the horizontal channel 242 in order to facilitate the connection ofthe clip to the flange, but when connecting the opposite end of thepanel to the next adjacent flange 244 of an inverted T-shaped support,the clip, as seen in FIGS. 106 and 107 is compressed against the end ofthe panel so that the connector sheet 206 becomes fully inserted intothe horizontally opening channel 242 allowing the channel 226′ in theclip to be raised high enough to be in alignment with the associatedflange 244 and at that point in time, the clip can be pivoted outwardlyagain allowing the channel 226′ to receive the flange and allowing theconnector sheet 206 to be removed from the channel 242. As seen in FIG.108, the clips 240 at opposite ends of the panel have been mounted onassociated flanges 244 of inverted T-shaped supports and the connectorsheets 206 have been removed from the channels 242 so that the clipsform vertical covers over the ends of the panel and can be positioned inadjacent relationship with clips 240 of an adjacent panel. It will alsobe appreciated that the clips of adjacent panels engage each other sothat the inverted T-shaped supports are hidden from view once the panelshaving the clips thereon are suspended from the T-grid system.

Not all support systems for ceiling panels have support members ofinverted T-shaped cross section. Rather, as seen in FIGS. 109 and 110respectively, the support members 245 a and 245 b could be of generallyU-shaped channeled cross section having inturned lips 247 along the twoupper edges of the channeled support members. The channeled supportmembers could have various depths depending upon the aestheticappearance desired for the ceiling system and, for example, in FIG. 109,the channel 245 a is fairly shallow in relation to the channel 245 billustrated in FIG. 110. The more shallow channel can be seen to definea recess 249 between adjacent ceiling panels 50 whereas the deeperchannel 245 b can be seen to extend downwardly beyond the lower surfaceof the ceiling panels supported thereby.

An edge clip 251 for use with ceiling panels 50 to be supported by achanneled support system is also seen in FIGS. 109 and 110, and as willbe appreciated, the clip is designed to fit along the edge of the panel50 similarly to the previously described clips 218 or 240. The clips 251are elongated as with the previously described clips and are preferablyextruded members of a rigid material such as aluminum, plastic, or thelike. The clips define an open channel 253 that opens horizontally whenthe clip is in use on the edge of a panel as illustrated and defines avertical main flat body 255 with a lower lip 257 protruding horizontallyaway from the lower edge of the main flat body. A correspondinghorizontally extending lip 259 is provided away from the top edge of themain flat body with the upper horizontal lip being integral at itsdistal edge with a smaller channel-shaped portion 261 of the clip. Thesmaller channel 261 is in cross section of an inverted J-shapedconfiguration. The smaller channel also opens horizontally in the samedirection as the main channel and defines a vertical plate portion 263with an obliquely angled lip 265 along its lower edge and a horizontalextension 267 along its upper edge. The distal or outermost edge of theupper horizontal extension 267 has a downwardly depending lip 269forming a hook to complete the smaller channel.

The main channel 253 receives an edge portion of the panel 50 to whichit is to be connected in the same manner as the clips 218 and 240described previously. The smaller channel 261 is adapted to receive theupper edge of the U-shaped support member 245 a or 245 b with the hookportion of the inverted J-shaped smaller channel being supported by anupper edge of the U-shaped support member and the oblique lip 265engaging an outer surface of the U-shaped channel to positively butreleasably secure the clip to the U-shaped channel.

As can be appreciated, when a panel is to be connected to a U-shapedsupport member, the adjacent edge of the panel 50 with the clip 251thereon can be raised above the U-shaped support member and the invertedJ-shaped smaller channel 261 is moved over the associated side edge ofthe U-shaped support. The panel can then be lowered until the clip 251supports the panel on the associated side edge of the U-shaped supportmember. Of course, to remove the panel, the reverse process is followed.

Sometimes it might be desirable to fold a panel around a corner or toform a corner. With the panel of the present invention, such a fold orcorner can be made in an aesthetically attractive manner as illustratedin FIGS. 97 and 98. It will be seen in FIG. 97 that a divider 208including the connector sheet 206 across the top thereof can be severedfrom the remainder of the panel at the location where a fold or bend isdesired in the panel leaving the outer sheet 204 where the divider wasremoved. The remaining portions of the panel can be folded in onedirection or the other as illustrated in FIG. 98 so that one remainderportion of the panel is oriented perpendicularly to the other portionwith the outer sheet 204 extending continuously around the bend so as todefine a fully finished corner for the panel. Such a fold in the panelmight be desirable, for example, in a skylight where a window is raisedabove the ceiling level into an upwardly recessed area and by followingthe procedure shown in FIGS. 97 and 98, a panel or panels can be foldedto extend from the normal ceiling level up into the recessed area of theskylight.

As mentioned previously, the preferred material from which the dividersare made includes glass fibers and a mixture of a thermoset resin and athermoplastic resin. The material so formed wants to remain in a flatplanar orientation even after having been creased and folded asdescribed previously into the configuration of the divider asillustrated for example in FIGS. 89-91. In order to retain the foldedconfiguration with the side walls 214 of each divider folded inwardly,the panel 200 over a long period of time needs to be held in at leastsome compression or the folded side walls will fold outwardly in aneffort to return to the flat planar orientation. Of course, the dividerscannot return to the flat planar orientation as they are secured alongthe top and bottom to the outer sheet 204 and connector sheet 206 butthe side walls will over some period of time try to straighten out ifnot held in compression and when doing so, pass from their inwardlyfolded orientation of FIG. 89 to their outwardly folded orientation ofFIG. 88 wherein the side walls abut the side walls of adjacent dividersthereby being mutually reinforced and rigidifying the panel so that itis incompressible from a practical standpoint. A panel in itssubstantially incompressible condition is shown in FIG. 96. In otherwords, to maintain the compressible nature of a completed panel, thesidewalls need to be at least partially folded inwardly as shown inFIGS. 89-91.

The strips of material from which the dividers 208 are made are foldedin an unheated environment and a hot melt adhesive is applied to thestrips or to the outer sheet 204 and connector sheet 206 before they arelaminated together. As mentioned previously, unless the panels 200 aremaintained in a compressed configuration such as illustrated in FIGS.89-91, they will, over some period of time, expand into theconfiguration of FIG. 88 in which configuration the panel is no longercompressible. This time period over which it takes for the dividers toconvert from the configuration of FIGS. 89-91 to the configuration ofFIG. 88 is dependent upon a number of factors including the resin usedin the material from which the dividers are made and also whether or notheat is applied to the material while the dividers are in the compressedconfiguration of FIGS. 89-91. By adding heat to the dividers while theyare compressed, the time period it takes for them to expand into theconfiguration of FIG. 88 is lengthened. Also, by increasing the percentof thermoplastic resin used in the material from which the dividers aremade, the time in which it takes for the dividers to transform from theconfiguration of FIG. 89 to the configuration of FIG. 88 can beincreased. By way of example only, the time period for thetransformation may be varied anywhere from 15 minutes to 32 hours.

Accordingly, when the panels 200 are formed and shipped, they aredesirably shipped in a compressed state so that a relatively largenumber of panels can be packed and shipped in a relatively smallcontainer particularly in comparison to conventional acoustical tiles ofa fixed depth, i.e., a depth similar to the fully expanded depth of apanel 200 in accordance with the present invention. Once the panels areremoved from the shipping container, however, they expand immediatelyfrom the configuration shown in FIG. 91 through the configuration shownin FIG. 90 to the configuration shown in FIG. 89. They will remain inthe configuration of FIG. 89 for the above-noted time period after whichthey will transform into the configuration shown in FIG. 88 where thepanel becomes incompressible from a practical standpoint. During thattime period, the panels can be cut to their desired shape and installedin a supporting grid system before the panels become substantiallyincompressible. They can therefore be flexed for easy insertion into theopenings defined between support members in the supporting grid systemif inserted before becoming incompressible.

As mentioned previously, panels formed in accordance with the presentinvention have desired acoustical properties that can be variedaccording to various parameters. In comparing one embodiment of thepresent invention with conventional acoustical tiles, one can see theacoustical benefit obtained from a panel formed in accordance with thepresent invention. In FIG. 99, a graph comparing the panel of FIG. 14 ofthe present invention with other acoustical tiles is illustrated. TheX-axis references frequency in hertz while the Y-axis references a noisereduction coefficient. The three panels compared to the panel formed inaccordance with FIG. 14 of the present invention are a hard mineralacoustical tile panel manufactured by Armstrong under the trademark“Cirrus,” a glass fiber tile of two-inch thickness manufactured byEcophon of Sweden under the trademark “Focus,” and a 0.7 mm metal panelwith perforations and an overlying sheet of a non-woven fleecemanufactured by Hunter Douglas of Rotterdam, Holland, under thedesignation Luxalon 300C.

As can be seen, the acoustical panel of FIG. 14 performs superiorly tothe three compared panels at lower frequencies as well as at fairly highfrequencies and performs comparably at intermediate frequencies.

Although the present invention has been described with a certain degreeof particularity, it is understood that the present disclosure has beenmade by way of example, and changes in detail or structure may be madewithout departing from the spirit of the invention as defined in theappended claims.

1. A structural panel having an outer layer and a cellular structure,said cellular structure being made of a fiberglass matting comprised ofa glass fiber matrix bonded with a polyacrylic acid.
 2. The panel ofclaim 1 wherein the glass fibers in the matrix have diameters in therange of 3 to 20 microns.
 3. The panel of claim 2 wherein said glassfibers are approximately the same length.
 4. The panel of claim 3wherein the length of the glass fibers is approximately 0.75.+-0.0.08inch.
 5. The panel of claim 2 wherein said glass fibers are shorter than3 inches.
 6. The panel of claim 1 wherein said cellular structure iscompressible.
 7. The panel of claim 2 wherein said cellular structure iscompressible.